WASHINGTON — Celebrating the ethnic diversity of America, President Barack Obama said more than two dozen foreign-born service members who became U.S. citizens at a White House ceremony on the Fourth of July are vivid reminders that the country is, and always has been, a nation of immigrants.

He said the vast range of backgrounds and experiences that made America a melting pot for more than 200 years also makes it stronger, but that the immigration system has to be retooled for the U.S. to keep its place as the greatest nation on earth.

“If we want to keep attracting the best and the brightest from beyond our shores, we’re going to have to fix our immigration system, which is broken,” Obama said after 25 service members from 15 countries raised their right hands and pledged allegiance to the United States. “Pass common-sense immigration reform.”

In the evening, Obama and his wife, Michelle, were welcoming a larger group of service members, including the new citizens, to an all-American barbecue on the South Lawn, along with prime seating for the fireworks on the National Mall.

While state education officials are sharing their proposals aimed at ending the teacher shortage in Colorado, the state’s largest teacher association says the overall plan lacks specifics and shortchanges traditional preparation programs.